They Don’t Tell You: The Current Global Warming Trend is Over 300 Years Old

A Scene on the Ice by Hendrick Avercamp, circa 1600

Satellite data only goes back to 1979, and global land-thermometer records only go back to 1850. Before that we have to resort to “proxies”, which are various natural phenomena from which temperature can be deduced. As we go further back in time, the errors and uncertainties increase.

Charles III of Habsburg, 1707 Francesco Solimena

Here is a best estimate of the global air temperature for the last 2,000 years, using the best available source for each period:

1850 – 1979: Land thermometer record (HadCrut3, from the UK Met Office Hadley Centre and the Climatic Research Unit, slightly less tricked up than the GISS data of Figure 13).

16 AD – 1850: Loehle’s reconstruction in 2007 based on all temperature proxies except tree rings. It used 18 proxies over a wide geographical range, including sediments, boreholes, pollen, oxygen-18, stalagmites, magnesium to calcium ratios, algae, and cave formation. First reconstruction in which every proxy was calibrated to temperature in a peer reviewed article; arguably about as good as it gets. (Tree rings make poor proxies: Tree growth depends heavily on water and mineral availability so it is often not proportional to temperature as assumed, tree populations genetically adapt to climate change so long term climate trends fade out, and individual trees respond differently to temperature so the choice of which individual trees to examine introduces subjectivity and bias. See page 1050.) (A second high quality reconstruction, with 30 proxies including six tree rings, but no bristlecone pines, was made by Ljungqvist in 2010. It basically confirms Loehle’s results, estimates the current air temperature as about 0.1°C less than its medieval peak in 950 AD, and confirms the start date of the current global warming as just before 1700.)

(Technical note: The three data sources are spliced together by simply resetting their anomaly origins so that the average of overlapping periods are equal. The annualized satellite and the land-thermometer data was smoothed with a five year filter. To avoid a discontinuity moving from land-thermometer to satellite data, the land-thermometer temperature was used for 1979, and the midpoints between the land-thermometer and satellite temperatures were used for 1980 and 1981.)

The land thermometer records exaggerate the rate of warming using the tricks documented in parts 1 and 2 of this series, but they are the best data we have for 1850 – 1979. However we need a rough idea of historical temperatures in that period to make several crucial points, so we will go with that data.

Figure 17: The best and latest temperature picture. The current global warming trend started around 1670 to 1700, some 310 years ago. The current temperature is probably less than the medieval peak—the land thermometer data from 1850 to 1980 exaggerates temperature increases, though no one knows by how much. Sources: See text above.

The current global warming trend started before 1700, some 310 years ago. That was pre-industrial, so a natural climate force must have started the current global warming trend.

That the medieval warm period existed is well documented in European history. That it was worldwide is verified by hundreds of peer-reviewed studies, by over 700 scientists from over 400 separate research institutions, most of whom found that the period was probably warmer than today. The studies are from all over the world (except Australia)—here is a stunning illustration that makes that point.

Likewise the little ice age is well documented in European history. It forced an end to the Viking colonization of Greenland in about 1430, the Thames River in London froze over most winters but the last time it froze was 1804, and in the 1600s and 1700s animals in Europe would die of cold inside barns which never happens now. Like the medieval warm period, temperature proxies around the world confirm that it was worldwide.

This temperature picture here broadly agrees with what the climate establishment believed until 1996:

Figure 18: The climate establishment’s temperature picture in 1990, with the current global warming trend starting around 1650. From the First Assessment Report of the IPCC, page 202.

Figure 19: The climate establishment’s temperature picture in 1995, with the current global warming trend starting around 1680. From the Second Assessment Report of the IPCC, 1996, via here.

They Don’t Tell You: Global Warming Alternates With Global Cooling Within the Trend

If we zoom in on just after 1850 (when the thermometer data starts—proxies are too imprecise to determine turning points), we can see an interesting pattern:

Figure 20: Alternating periods of warming and cooling, within the overall warming trend. The periods last about 20 – 33 years each. Warning: This is land thermometer data, which has been subjected to tricks and revisions (especially 1940 – 1975)—the turning points shown are the generally agreed ones, except that 2002 is still ambiguous because it is not yet confirmed by a definite subsequent decline (see Figure 14 in Part 2 ). Source: Figure 17.

If the pattern continues, the next 12 – 35 years will see cooling.How many in the public or the political class are aware of this pattern? Everyone has heard the climate establishment’s forecast that the strong warming of the last three decades will continue while we continue emitting CO2. But the establishment do not tell people that some or all of that strong warming since 1975 is due to a cyclic phenomenon that is now entering a cooling phase.

Something that has always bothered me a little is the fact that the Little Ice Age (LIA) and Medieval Warm Period (WMP) appear to have a global temperature anomaly difference of just ~1C in many reconstructions. The historical records, on the other hand, seem to indicate that the real temperature difference between these periods was rather higher: Since Vikings were farming and living in parts of Greenland that were then ice-free, and in the LIA the Thames would freeze over, etc. http://en.wikipedia.org/wiki/River_Thames_frost_fairs

It could be that the qualitative historical climate records look more “extreme” than a 1C difference since the 1C difference was operating over 100-150 year time scales. This might eventually cause large scale changes in ice cover.

But substantially larger temperature differences in specific regions (like England) are not really apparent in e.g. the MWP map that Jo linked to above.

Are the proxies always normalized against the measured land based thermometers or does it depend on the study?

This I think is a simple and compelling illustration of David Evans’s point. It’s simple in that it is based on one temperature record (the oldest continual instrument based record in the world) and plainly shows how – at least in Central England – temperatures have been increasing, by fits and starts, since the late seventeenth century. It has the useful advantage of also showing CO2 emissions during that period. Two interesting features are (1) that the longest and steepest increase was from around 1695 to around 1735 and (2) that the warming trend in the late seventeenth and early eighteenth century appears to have been more marked than the current trend. In other words, there’s nothing particularly remarkable about the late twentieth century.

It always gets down to the money. As the prophecies of catastrophic warming continue to fail the voters will punish politicians at the ballot box. I believe CAGW is experiencing it’s death throes. Unfortunately, those intellectual parasites who leach off of the taxpayer are laying the groundwork for their next scam. The only question is, what will it be (e.g. Ocean acidification, biodiverity)?

Further to my earlier post this shows that late seventeenth / early eighteenth century trend even more clearly. It’s from the late John Daly’s excellent website “What the Stations Say” – well worth a detailed look.

It always gets down to the money. As the prophecies of catastrophic warming continue to fail the voters will punish politicians at the ballot box. I believe CAGW is experiencing it’s death throes. Unfortunately, those intellectual parasites who leach off of the taxpayer are laying the groundwork for their next scam. The only question is, what will it be (e.g. Ocean acidification, biodiverity)?

Eddy,

You have it right. There will always be another snake-oil salesman. Ocean acidification looks too easy to shoot down though. PH test kits are too easily available (well that’s simplified a bit). In any case actual measurements are easy to make and very hard to counter. I would think that the cause du jour will be a more directly political one this time around. Let’s say, rich nations oppressing the poor nations. This is already in the pipeline just waiting to take over.

The “next big thing” will be, I predict (and you heard it here first) — Water:

“Industrial processes consume considerable water resources, and some nations are using more than their fair share on a global per capita basis, so developed countries should commit to water usage limits, under a cap and trade system, administered by the United Nations Framework Convention for Water Utilisation (U.N.F.C.W.U) … dee dah, dee dah, dee dah”.

All that particular scam is waiting for is the final death rattle of the AGW scare, and a catchy name or three-letter-acronym (TLA).

The existing Carbon markets could trade water just as well as carbon, you might even be able to trade carbon allocation units in exchange for water allocation units …

This is the part of the story where you really have to tighten your seat belt firmly and rely on your religion to believe in the “scare the living bejesus out of children” movement . Notice in the text under figure 20 where it says:

Warning: This is land thermometer data, which has been subjected to tricks and revisions (especially 1940 – 1975)…

As amazing as it might seem, even today the land based temperature readings from this era magically keep changing. See Thermometer Magic or Gissmatic for just two of bazillions of examples.

The “next big thing” will be, I predict (and you heard it here first) — Water:

Rereke,

You intrigue me. What, pray tell, will be their proposed solution? Perhaps that the developed nations ship their water to the undeveloped nations a la the AGW solution that we ship a lot of our money to them? It doesn’t ring quite plausible. Trading water credits??? I’m hard put to take it seriously. How does U.S. water consumption hurt any other nation for instance? I can’t see how they can make a case for it.

On the other hand, three years ago I never would have believed that the U.S. could fall for the likes of Obama. We live in strange times. And I might add, dangerous as well.

Yes, we lay people do understand the cheating, since it’s been so shoddy and blatant. Think Hockeystick, think Anthony Watts’ great work on weather stations.

Something that’s been on my mind is the upsurge of a subtler danger: the moderates and lukewarmers. These are people who are often acceptable to the skeptic community, are critics of Mann, Hansen etc and side with skeptics on many issues.

I’d like to ask: which of these two is more dangerous?

Firstly, we have a soon to be discredited alarmist who talks of 100 metre sea level rises, global climate disaster…to be offset by inadequate energy supply, carbon taxes and emissions trading.

Secondly, we have a moderate who believes that the climate establishment has disgraced itself by distorting or even falsifying the climate records, who is an acceptable voice to skeptics, has some concern for man’s effect on climate…and believes in offsetting that effect by inadequate energy supply, carbon taxes and emissions trading.

See where I’m going? If “moderation” has the same result for humanity as the worst alarmism, skeptics will win the war and lose the peace. If the windmills line the hills, Gillard and the Greens get to suck a whole new consumption tax into their maws, and Goldman Sachs get to live out the wet dream of Enron and Lehman Brothers, what will it help if Al Gore has to give back his Nobel Prize? Or if the yachts can’t have their annual circumpolar race?

Unless we achieve an abundant energy supply, no carbon tax, no ETS, we lose. That urbane and reasonable moderate who gets to write a well received article on your favourite skeptic website could be the biggest danger of all.

There are always several “next big things” that are waiting to be deployed by the media and policy players. I suspect the next one will need to drive a significant distraction away from Climate Change as it’s a hot potato. You’re looking at one right now – the internet, since it is the primary reason why the Climate Change agenda has unraveled. I won’t be surprised to see the internet come under increasing attack from policy makers and perhaps even some form of internet attack/virus that drives the debate to a new global internet policy. Microsoft are already proposing to isolate “infected” computers from the internet.

A new War will also offer the usual distraction and provide some with a new income.

Curious Canuck says:
“Hey Anothony, story potential maybe. I was just hopping around through Wikipedia and stumbled across some heavy noting on Joanne Nova’s entry so peeked into discussion and William M Connolley was at play. I followed the conversation and links to this page…

Wikipedia:Articles for deletion/Joanne Nova…
Do I read this right? That short days after the last trouble Connolley caused there that he has just led a failed attempt to have Ms. Nova erased from Wikipedia history?
This would be interesting follow-up in a piece to “Connolley may be out at Wikipedia Posted on August 24, 2010 by Anthony Watts ” Maybe help examine and discuss just what was decided on Connolley and the time frame it all transpired in as voting seemed to take forever.
“The result was keep. — Cirt (talk) 11:02, 4 October 2010 (UTC)” … Thank goodness.

Emergence from the LIA, which we discussed in college class almost 40 years ago, we used Lamb’s book (new at the time). (I wonder if anyone in a college course in climate knows what that book is any more, probably not.)

Bears repeating though.

Or perhaps not. The Earth is only about 100 years old, and CO2 has been a constituent of the atmosphere only for about the past 40 years or so.

The many temperature graphs there generally show that current temperatures are around the MWP temperatures. At least one of the papers suggests that solar variability is the best explanation of temperatures over the last 2000 years, which is what most climate scientists believe (except for the last 100 years, of course ).

Looking at quite a few of the graphs there is a bit of a problem, in that the time corresponding to the MWP differs a bit from study to study. It seems to happen somewhere between 800 – 1300.

Rereke Waakaro # 13
Intriguing post.
“Water, water everywhere nor any drop to drink.”
The Rime of The ancient Mariner
In Fresno County, California, the most agriculturally intensive county on the planet, the enviro loons have managed to turn off the spigot. It is now a dust bowl. Fortunately , even as food prices rise we can all sleep better knowing that the US Government is doing all it can to save the darter smelt from extinction. Sure, Fresno County has 20% unemployment but think about future children having bait for their line?!

Maybe I was wrong. Mabel it isn’t all about the money. Maybe it is all about the children. Perhaps if they cannot control the air people exhale they can control us by limiting the water we drink? I am sure the compassionate greens would never make a video showing children dying of thirst? That would be too cruel. I am sure they would make the little ones death more humane. Hmm… Maybe just blow them up? Oh yeah, they have already done that!

Thanks for the neat presentation. Could be improved by making the temp lines wide and fuzzy to admit that there are errors of certainty.
Sadly, when there is political intent one has to be more scrutinising of any data so, the last 20 years are questionable.
As for the next calamity,- I’d willingly believe in a repeat of the 1859 solar storm which caused fires in some of the early telegraph stations. NASA reckons a repeat performance is quite on the cards given the strangely quiet nature of the current solar cycle. Perhaps they’ve got a political/funding bias?

To commemorate the 10:10 eco-snuff movie, I would like to suggest that October 10 henceforth be celebrated worldwide as Climate Fools Day.

Let this day forever be a reminder of how the eco-fascists blew themselves up with their own hateful propaganda, marking the beginning of the end of the global warming scam.

Can our internet-savvy friends please help create a website–something along the lines of “climatefools.org”–with links to the 10:10 eco-snuff movie. The objective is to shame these green bullies and remind them that civilized people won’t tolerate their unacceptable fascist behavior.

e.g. text on website page:
—————————–

-Ticking countdown- LEFT TO CLIMATE FOOLS DAY!

CLIMATE FOOLS DAY is a day of peace and sanity where the free peoples of the world celebrate:

- The end of eco-fascism
- Electricity and all its life-enriching benefits
- Oil and coal and all their life-enriching benefits
- Cows and all their tasty benefits
- All the good things about protecting and caring for our environment, minus the fraud that is carbon taxation, emissions trading, biofuels and other unproven renewable energy technologies

Perhaps that the developed nations ship their water to the undeveloped nations …

It has been done before. Have a look at “The Frozen Water Trade”, by Gavin Weightman. In the 19th century, ice was cut from the lakes of New England — valued for its incredible purity — and shipped firstly to the southern states — Florida, Alabama, etc. And then the following year, to India so that the British Rhaj could have have ice in their gin and tonics.

Not that I am serious about starting that trade again (think of the carbon emissions … oh, but we are past that … sorry, I forgot).

… a la the AGW solution that we ship a lot of our money to them?

Well, yes. It is all about, and always has been about, “equitable distribution and utilisation of resources”.

“From each according to his means, to each according to his needs”. Karl Marx.

The developed countries use more oil than the undeveloped countries, so there won’t be any left when the undeveloped countries get developed enough to want to use it. And that is not fair, so the developed countries have to share.

Seriously, some of the politics behind the succession of scares, and the accompanying propaganda, are that childish.

For a dead man Karl Marx sure casts a long shadow. But the sharing thing sounds good. I’ll gladly send Obama and several hundred assorted Senators and Representatives to any underdeveloped country that wants them!

And if it is just a part of the warming that has been going on for 300 years, how come you try to argue so much that it hasn’t been happening. I wish you’d stop contradicting yourself!! It makes you appear very foolish!!

I knew I’d find the unintelligent troll that’s been thumbing-down just about everyone – at least until you got bored with it.

What’s actually making YOU the foolish one is your apparent lack of knowledge. Natural warming has nothing to do with GISS’s data manipulations and the planet obviously doesn’t care for political agendas. We just want the truth, and not pay exorbitant taxes to “solve” a non-problem that can’t and won’t be.

Twinkler, you can give as much as you like to murderous despotic Robert Mugabe. I’m sure he’ll thank you..

During the good’ol days Sweden used to be superpower of Europe and a small
event in our war history is about how we stopped the Danish rebellion by marching
over the frosen straights of Small and Large Belt.

This was regarded as impossible so the Danish was a little bit supprised when
the whole f-ckn Swedish army suddely knocked on the door of Copenhagen.

Now one ever tried it ever since… Oh yes the warming started long before human
CO2 emission where measurable!

Sweden had a very large empire, spanning much of Northern Europe, including Russia. Then they “got bored”, packed up and left.

But not before signing up to the various treaties that made the Peace of Westphalia effective ending the 30 Years War; which notably set the rule that you don’t fiddle with the internal affairs of sovereign nations other than your own. Can we get the UN to sign up?

Jo, you are cherry picking data points in Figure 20, and claim that the 1950s were a decade of cooling. Move the 1942 cherrypick five years in advance and suddenly the 50s is “warming”. Very poor statistical methods, Jo.

Also, the Medieval warm period/little ice age were probably confined to Europe and were probably caused by internal climate variability, so your plots are not of global temperature. Where is the evidence that the MWP was due to a global forcing? Even MacShane/Dwyer’s plot, lauded on this site, has no MWP. You are making such a basic mistake here it is embarrassing: local temperature trends are not the same as global temperature trends. Simple statistics! Let me give you a simple example: suppose three longitudinal sections of earth, covering earth, had average temperatures over 30 years of (11, 13, 15). Suppose the following thirty years the section averages were (11, 12, 18). The middle region has declined in temperature but the global average temperature has increased.

After all your years of blogging on climate change it is surprising you don’t get what climate change even means. You say in your annotation of figure 17: “The current temperature is probably less than the medieval peak”. But there is no evidence that the medieval peak was global, so you are comparing the global average temperature now with the temperature at a specific time and a specific region (MWP). Embarrassing statistical methods Jo, didn’t they teach you better in biology? (Actually I’m sure they did, but I have a hypothesis as to why Jo makes such simple “mistakes” that her readers are incapable of spotting. Perhaps it’s something to do with donations, Jo?)

How is it that some temperature records are fine and others must be “exaggerated by tricks”? Those that are inconvenient to your beliefs must be fraudulent, yes?

Gotta love that the IPCC’s 1990 report was ok enough for you to publish their plots (figure 18). If the IPCC are untrustworthy, why are you using any of their plots? You claim that IPCC are fraudulent, so by your reasoning, wouldn’t figures 18 and 19 be unreliable?

Finally, by looking at a single time-series like figure 17, there is no way of telling what the causes of any of the trends are; we have no way of knowing whether the current warming trend has the same cause as some (undoubtedly natural) warming trend in the past. We need to use other lines of evidence to work out what the current trend is caused by! (Let me spell it out for the simpletons: there is a global warming trend now and there was a global warming trend 10 000 years ago. We cannot conclude, by looking at a graph of global temperatures, that both warming trends had the same cause).

Some icing: that current temps match some temps in the past is almost irrelevant. The concern is that the current temps are caused by GHGs that humans are producing and continue to produce rapidly. That implies that the warming trend will carry on aggressively, and won’t turn down like it did 6000 years ago (a trend which was caused by changes in the configuration of earth’s orbit).

Indeed, it has been concluded that compulsory population-control laws, even including laws requiring compulsory abortion, could be sustained under the existing Constitution if the population crisis became sufficiently severe to endanger the society.

One supposes that a multi-secular warming confined to Europe (and Greenland) is a possibility. The proposition is, however, so unlikely as to be fantastic.

Sadly, warmists have learned they can claim anything, confident that the MSM will not call them to account. A perfect example of this is Robyn Williams’ prediction of a possible hundred metre sea level rise. Yet as absurd as that was, oh dear’s “confinement” theory rates as one of the most extravagant to date.

I have also looked at long-term temperature trends at various worldwide locations and cannot find evidence of alarming recent temperature increases (except in urban locations, as one would expect. There have been variations to either side of the general trend since the 1700s but the variation in recent times is of similar or less magnitude.

The De Bilt trend is similar to that reported from England by Robin Guenier (above), although the overall trend at De Bilt was a bit greater at +0.5 degC/Century. So, this long-term trend makes a mockery of the claimed strong correlation between temperature and CO2 levels.

The MWP probably oscillated back and forth between hemispheres, but the majority of proxies that reproduce the MWP have been found in Europe.

It was still a local phenomenon however. No evidence has been found that suggests that the MWP was due to anything other than internal climate variability; that is, there is no evidence to suggest that it was caused by a global forcing.

Absence of proof is not proof of absence. There are obviously too many proxies showing the MWP because some “scientists” have been discarding such data in order to fit history to their models.

The prevalence of “proxies” is a result of the progress of science, the written history and the proportion of land and water areas in each hemisphere.

The thermal buffering of water results in “global” pertubations of climate being dampened more in the southern hemisphere. Also, there being less land in the southern hemisphere, there is a lower probability of finding “proxies”.

“Global” warming in the late 20th Century is “evident” mainly in the northern hemisphere. And were it not for dubious extrapolations, one would probably see that the temperature changes are regional and transient. As they have “always” been.

The points you raise are not evidence. What you need to do is provide evidence. Someone’s misrepresentation of some other guy’s opinion is not evidence.

“Some other guy’s opinion” that you are dismissing was authored by John Holdren who happens to hold a fairly senior position on the world stage right now. The so-called misrepresentation includes both direct quotes and scanned pages from the book.

If you don’t consider the contents of a book the be evidence of what an author of said same book wrote then I suggest you probably have not the slightest idea what evidence actually is (or possibly might be deliberately devious in the hope of confusing a few readers).

[...] *PS: People still write to me and ask me how to reply to the oft repeated line about 2010. It’s also handy to mention that the world has been warming since before Napolean bought all those SUV’s. (The warming started before our emissions became significant, and at least since measurements began, the trend hasn’t changed and the models don’t know why. We also discussed this point in the here too, with other graphs.) [...]